Aythya marila is 41-51 cm in length.
Males tend to have a greater mass, 1134 grams on average, than females,
907 grams on average (Palmer, 1976). Males have dark heads, necks, and
rumps, a gray back, white flanks, and a blue bill. The head of the male
has a greenish sheen in full sunlight. Females have brown bodies with
a white oval patch behind the bill. When in flight, a white wing stripe
is obvious, extending from the secondaries to the primaries (Bellrose,
1980).

Status
in Estuaries

This semi-colonial species prefers to nest
on the ground on the edges of ponds and lakes in open or forested tundra,
and on islands in large taiga lakes. A typical includes 7-10 dark olive
buff eggs in depression supported by tall, dead marsh grass, within
50 feet of the water. Young are precocial (Ehrlich et al., 1988).In winter, most greater scaup forage in large flocks in open bays
and estuaries on the Atlantic and Pacific coasts. The maximum age of
a greater scaup recorded in nature is approximately 22 years.

Abundance
and Range

During the breeding season, the majority of
North American greater scaup occur along ponds in the treeless coastal
tundra of western Alaska. The Alaskan breeding population has been estimated
at 550,000 (Bellrose, 1980). Bird counts indicate that during winter,
approximately 330,000 greater scaup occur in bays and estuaries of the
Atlantic coast, between Massachusetts and the Chesapeake Bay (Bellrose,
1980). Smaller winter populations are found north to Canada, south to
the Gulf Coast, on the West Coast from Alaska to Baja, and on the Great
Lakes (Bellrose, 1980).

Site
Fidelity

Uncertain for breeding grounds, but adults
and young seem to have a strong homing ability (Bellrose 1980). Banding
data indicates that most adults return to the general vicinity of their
previous years wintering spot, if not the exact location.

Generalist. The greater scaup forages in 1
to 10 meters of water by diving for benthic organisms. In the winter,
clams make up a large portion of the diet, especially in marine habitats.
However, this species is opportunistic, and eats a wide variety of bivalves,
gastropods, crustaceans, vascular plants, and algae. In freshwater habitats,
plants often dominate the diet (Bellrose 1980).

GRSC were collected from Niagara
County and Suffolk County, New Yorkbetween
1977 and 1980 (Kim et al., 1984). Residues of organochlorines in
subcutaneous fat ranged from ND-1.60 µg/g wet weight DDE,
from 2.10-15.0 µg/g PCBs,
and from ND-0.38 µg/g mirex.
Residues in breast muscle ranged from 0.01-0.14 µg/g DDE,
and from 0.11-2.20 µg/g PCBs.
Mirex was detected in one
muscle sample, at 0.14 µg/g. Residues in liver ranged from 0.01 -0.07
µg/g DDE, and from
0.22-2.10 µg/g PCBs. Mirex
was detected in one liver, at 0.09 µg/g. One brain contained DDE
at 0.01 µg/g. Residues of
PCBs in the brain ranged from 0.02-1.90 µg/g. Mirex
was detected in one brain, at 0.04 µg/g.

GRSC were collected in Gdánsk Bay,
Poland in 1980 and 1981 (Falandysz and Szefer, 1982). The concentration
range for HCB in fat
of males was 0.08 to 0.55 ng/g lipid weight, with a mean of 0.25 ng/g.
In females, the range for HCB
was 0.07 to 1.10 ng/g, with a mean of 0.23 ng/g. Residues of
-BHC
were detected in females only, with a concentration range from ND to
0.03 ng/g, and a mean of 0.001 ng/g. In males,
-DDT
ranged from 0.71 to 4.70 ng/g, with a mean of 2.20 ng/g. In females,
-DDT
ranged from 0.63 to 4.00 ng/g, with a mean of 1.80 ng/g. In males, PCBs
ranged from 2.50 to 28.0 ng/g, with a mean of 10.0 ng/g. In females, PCBs
ranged from 1.60 to 33.0 ng/g, with a mean of 8.00 ng/g. Residues of
-BHC
were ND in all samples.

Males were collected from 2 sites in
San Francisco Bay: Alameda Flood Control Channel (AFCC) and a location
in the center of the Bay (CSFB) in the winter of 1986-87 (Hothem et al.,
1998). Geometric mean oxychlordane
in carcasses from the AFCC and CSFB was 0.01 and 0.02 µg/g wet weight,
respectively. Residues of trans-nonachlor were not reported at AFCC, and had a
geometric mean of 0.01 µg/g at CSFB. Residues ofo,p’-DDT
were not reported at AFCC, and had a geometric mean of 0.01 µg/g at
CSFB. Residues of HCB were
not reported at AFCC, and had a geometric mean of 0.01 at CSFB. Dieldrin was ND at both sites.

GRSC were collected from Connecticut
waters of Long Island Sound between November 1992 and March 1993
(Barclay et al., 1995; Perkins and Barclay, 1997). In abdominal fat,
mean PCB concentration was 7.05 µg/g wet weight in November, 11.4
µg/g in December, 11.6 µg/g in January, 12.6 µg/g in February, and
11.0 µg/g March. In breast muscle, mean PCB
concentration was < 1.00 µg/g for all months. In abdominal fat, mean
total DDT was 1.20 µg/g in
November, 1.72 µg/g in December, 1.68 µg/g in January, 2.03 µg/g in
February, and 1.25 µg/g in March. In breast muscle, mean total
DDT concentration was < 0.10 µg/g in all months.

11.

GRSC were collected from the Detroit
River and from Lake Erie between 1993 and 1994 (Mazak, 1995). Ducks were
separated into the categories " macrophyte consumer" and
" zebra mussel consumer" based on gut content analysis and
stable isotope analysis of wing tissue and prey items. Mean liver
pentachlorobenzene for Detroit River macrophyte consumers (DRMA)
was 3.50 µg/g lipid weight, for Detroit River mussel consumers (DRMU)
was 4.90 µg/g, and for Lake Erie mussel consumers (LEMU) was 3.60 µg/g.
Mean dieldrin for DRMA was
24.0 µg/g, for DRMU was 34.0 µg/g, and for LEMU was 322 µg/g. Mean HCB
for DRMA was 13.0 µg/g, for DRMU was 36.0 µg/g, and for LEMU was 30.0
µg/g. Mean DDE for DRMA
was 20.0 µg/g, for DRMU was 314 µg/g, and for LEMU was 437 µg/g. Mean
OCS for DRMA was 23.0 µg/g,
for DRMU was 892 µg/g, and for LEMU was 329 µg/g. Mean mirex
for DRMA was 0.80 µg/g, for DRMU was 12.0 µg/g, and for LEMU was 7.30
µg/g. Mean residues of total PCBs
for DRMA was 185 µg/g, for DRMU was 1462 µg/g, and for LEMU was 4464
µg/g. Mean residues of PCB congeners
in DRMA ranged from 0.60 to 24.0 µg/g. Mean residues of PCB
congeners in DRMU ranged from 1.00-221 µg/g. Mean residues
of PCB congeners in LEMU ranged from 5.60-624 µg/g.

12.

Males were collected from several
sites on or near federally owned wildlife refuges in Rhode Island,
Connecticut, New York, and New Jersey in the winter of 1996-97 (Cohen,
1998). In abdominal fat, mean DDE
ranged from 0.39 to 3.64 µg/g lipid weight, depending on collection
month and location. Mean PCB in
fat ranged from 2.03 to 27.5 µg/g. All other organochlorines were
detected in fewer than 50% of the samples.

II.

Cholinesterase-Inhibiting
Pesticides

No direct exposure data available

III.

Trace Elements,
Metals, and Metalloids

1.

GRSC were collected from San
Francisco Bay, California, and Bear River National Wildlife Refuge, Utahin the winter of 1970-71 (Baskett, 1992). Breast muscle Hg
in birds from California ranged from 0.19 to 0.44 µg/g wet weight in
immatures and from 0.28 to 0.68 µg/g in adults. Breast muscle Hg in 1 bird from Utah was 0.02 µg/g.

2.

Four GRSC were collected from the
British coast between 1971 and 1972 (Dale et al., 1973). Liver Hg
residues were 9.1, 5.3, 1.9, and 9.9 µg/g dry weight.

3.

GRSC were collected from several
locations in New York State (Baker et al., 1976). Residues of Cd were detected at 2.00 µg/g wet weight in the liver of one
specimen, but were ND in all other samples. Residues of Pb
were detected in the liver of one specimen at 10.0 µg/g, and in the
breast muscle of another specimen at 2.00 µg/g, but were ND in all
other samples. Residues of Hg were detected in one liver sample at 0.02 µg/g. Residues
of Hg were detected in 3
muscle samples at 0.02, 0.08, and 0.10 µg/g.

GRSC were collected from Raritan Bay,
New Jersey (Gochfeld and Burger, 1982; Burger et al., 1984).
Concentrations of Hg and Pb
were reported in a figure only, so the concentrations in this synopsis
are approximate. Mean liver Hg
was 0.40 µg/g wet weight, mean Pb
was 0.60 µg/g, and mean Cd
was 0.51 µg/g.

GRSC were collected in Gdánsk Bay,
Poland for soft-tissue and feather metals analysis between 1980 and 1984
(Szefer and Falandysz, 1987). In soft tissues, mean Fe
ranged from 45.0 µg/g wet weight in the brain of males to 420 µg/g in
the lung of females. Mean Fe in
feathers was 1700 µg/g in males and 900 µg/g in females. Mean Zn
in soft tissues ranged from 10.0 µg/g in the skin of females
to 34 µg/g in the stomach of males. Mean Zn
in feathers was 130 µg/g in males and 120 µg/g in females.
Mean Mn in soft tissues
ranged from 0.32 µg/g in the skin of males to 3.50 in the liver of
males. Mean Mn in feathers
was 32.0 µg/g in males and 18.0 µg/g in females. Mean Cu
in soft tissues ranged from 1.10 µg/g in the skin of males to 17.0 in
the liver of females. Mean Cu
in feathers was 10.6 µg/g in males and 7.90 µg/g in females. Mean Pb
in soft tissues ranged from 0.05 µg/g in the brain of females to 0.95
in the eyeballs of males. Mean Pb
in feathers was 4.40 µg/g in males and 4.00 µg/g in females. Mean Cd
in soft tissues ranged from 0.03 µg/g in breast muscle of both sexes to
1.29 µg/g in kidney of males. Mean Cd
in feathers was 0.30 µg/g in males and 0.38 µg/g in
females. Mean Co was <
1.0 µg/g in all tissues. Mean Ni
was < 1.00 µg/g in all soft tissues. Mean
Ni in feathers was 2.90 µg/g in males and 1.80 µg/g in
females.

13.

Eighteen GRSC were collected from San
Francisco Bay in March and April 1982 (Ohlendorf et al., 1986). Liver Ag
ranged from 0.39 to 3.1 µg/g dry weight, with a mean of 1.10 µg/g.
Liver Cu ranged from 28.0
to 159 µg/g, with a mean of 96.8 µg/g. Liver Hg
ranged from 2.30 to 20.0 µg/g, with a mean of 10.6 µg/g. Liver Pb
ranged from 0.34 to 3.10 µg/g, with a mean of 0.71 µg/g. Liver Se
ranged from 6.70 to 31.0 µg/g, with a mean of 19.3 µg/g. Liver Zn
ranged from 100 to 200 µg/g, with a mean of 151 µg/g. Residues of Cr
and Ni were detected in
fewer than 50 % of the samples. The geometric mean of kidney Cd
was 15.5 µg/g.

14.

GRSC were collected in Gdánsk Bay,
Poland for hard-tissue metals analysis in the winters of 1982-83 and
1983-84 (Szefer and Falandysz, 1986). Mean Fe
ranged from 120 µg/g dry weight in the wing bones of males to 510 µg/g
in the tracheal cartilage of males. Mean Zn
ranged from 110 µg/g in the skull of females to 260 µg/g in the upper
leg bones of females. Mean Mn
ranged from 3.60 µg/g in the wing bones of females to 10.9 µg/g in the
tracheal cartilage of males. Mean Cu
ranged from 1.10 µg/g in the wing bones of males to 5.60 µg/g in the
skull of males. Mean Pb
ranged from 0.50 µg/g in the wing bones of females to 19.9 µg/g in the
tracheal cartilage of females. Mean concentrations of
Cd, Co, Ni, Cr, and Ag
were < 1.00 µg/g in all matrices.

15.

Male GRSC were collected from San
Francisco Bay, California and/or nearby coastal sites in early and late
portions of the winter of 1986-87 (Hothem et al., 1998). For early
winter GRSC from the Bay, geometric mean liver residues of Cu,
Hg, Se, and Zn were
101, 2.37, 20.7, and 158 µg/g dry weight, respectively. Geometric mean
kidney Cd was 2.55 µg/g.
For early winter GRSC from coastal sites, geometric mean liver residues
of Cu, Hg, Se, and Zn
were 88.6, 4.24, 7.01, and 171 µg/g, respectively. Geometric mean
kidney Cd was 4.01 µg/g.
For late winter GRSC from the Bay, geometric mean liver Cu
at 2 collection locations was 104 and 65.8 µg/g. Liver Hg
at the 2 sites was 10.4 and 5.72 µg/g. Liver Se
at the 2 sites was 32.7 and 27.4 µg/g. Liver
Zn at the 2 sites was 174 and 162 µg/g. Kidney Cd
at the 2 sites was 13.4 and 33.9 µg/g. No GRSC were collected from
coastal sites in late winter.

GRSC were collected from Long Island
Sound, Connecticut in the winter of 1987-88 (Barclay and Zingo, 1993).
Mean Pb was 0.81 and 1.38
µg/g dry weight in liver and kidney, respectively. Mean Cr
was 1.02 and 1.85 µg/g in liver and kidney, respectively. Mean Ni
was 15.4 and 31.4 µg/g in liver and kidney, respectively. Mean Cd
was 2.91 and 13.6 µg/g in liver and kidney, respectively.

18.

GRSC were collected in the Lake
Ijsselmeer-Lake Markermeer region of The Netherlands between 1987 and
1991 (De Kock and Bowmer, 1993). Mean liver
Cd was 2.7 µg/g ash-free dry weight.

19.

Adult male GRSC were collected from a
polluted site and a reference site in the San Francisco Bay area in
March, 1989 (Hoffman et al., 1998). At the reference site, liver Hg
ranged from 5 to 66 µg/g dry weight, with a geometric mean of 19 µg/g.
Residues of Se ranged from 7 to 23 µg/g, with a geometric mean of 13 µg/g.
Residues of Cd ranged from
1 to 17 µg/g, with a geometric mean of 3 µg/g. At the polluted site, Hg
ranged from 3 to 11 µg/g dry weight, with a geometric mean of 6 µg/g.
Residues of Se ranged from 21 to 140 µg/g, with a geometric mean of 67
µg/g. Residues of Cd
ranged from 1 to 7 µg/g, with a geometric mean of 4 µg/g.

Two dead and 4 dying GRSC collected
from Lake Houghton, Michigan in April 1928 were found to have 40 to 80 Pbpellets in their gizzards
(Van Tyne, 1929). The mass of Pb in the gizzards ranged from 3.5 g to 5 g. Living birds
exhibited signs of Pb
toxicosis, including recurring convulsions, excessive weakness, loss of
balance, and flickering irises. Post-mortem examination showed signs of Pb poisoning, including wasting of the internal organs.

2.

Adult males collected from San
Francisco Bay in March, 1989 were analyzed to determine the relationship
between Hg, Se
and Cd residues in liver
and the activity of several hepatic enzymes associated with glutathione
metabolism and antioxidant activity, and to determine differences in
enzyme activities and body, liver and heart weights between a polluted
site and a reference site (Hoffman et al., 1998). The concentration of
reduced glutathione (GSH) was inversely related to Hg
concentration. The ratio of oxidized glutathione (GSSG) to
GSH increased significantly with increasing hepatic
Hg concentration. HepaticGSSG
and glucose-6-phosphate (G-6-PDH) were significantly higher in GRSC’s
from the polluted site. The ratio of GSSG to GSH was significantly
higher in GRSC’s from the reference site.

IV.

Petroleum

1.

Approximately 71 GRSC died and
another 210 required rehabilitation following oil
exposure due to a small spill in the Firth of Forth, Scotland in
February 1972 (Bourne, 1972).

2.

Oiled GRSC (N=220) were recovered
after a 250-gallon spill of medium/heavy
fuel oil at Firth of Forth, Scotland in February 1978
(Campbell et al., 1978). Of these birds, 130 died of oil
toxicosis.

3.

Thirty-five GRSC were found dead from
oil toxicosis on Virginia
Beach, VA in 1985 (Virginia Department of Game and Inland Fisheries,
unpubl.).

4.

GRSC oiled
in a spill of diesel-Bunker C oil
mixture in Vancouver, British Columbia in February 1990 were captured
for rehabilitation (Harvey-Clark, 1991). Immediately after capture,
blood creatine kinase (CK) ranged from 1035 to 2470 IU/L, and averaged
20 times higher than the normal range for captive mallards. Immediately
after capture, blood alanine aminotransferase (ALT) levels ranged from
50 to 90 IU/L, which was 2 to 3 times higher than the normal range for
captive mallards. Nine days after capture, CK levels ranged from 125 to
1060 IU/L, which was within the normal range. Nine days after capture,
ALT was within the normal range. The elevated levels of CK and ALT seen
immediately after capture were associated with skeletal muscle damage
due to capture techniques, exacerbated by oil-induced
stress.

Koivusaari, J. 1976. Chlorinated
hydrocarbons and total mercury in the prey of the white-tailed eagle (Haliaeetus
albicilla L.) in the Quarken Straits of the Gulf of Bothnia,
Finland. Bull. Environ. Contam. Toxicol. 2:235-241.